An Experimental Investigation on the Forming Force in Asymmetric Parts Formed Using Single Point Incremental Forming

Single point incremental forming (SPIF) is used to form small batch production of different shapes of parts. Present study is focused on investigation of part asymmetry on the forming behavior of the parts formed using SPIF process. Wall angle as an asymmetry is considered for forming of the pyramidal frustrum. The wall angle is varied from 50 o to 65 o and subsequent forming forces are recorded using force dynamometer. It is observed that the increase in the wall angle for symmetric part results in increased formability to a threshold wall angle of 55 o , beyond which the formability of material decreases. For the asymmetric parts, the difference in the forming forces of forming different wall angles (50 o and 55 o ) is 28%. The difference in the forming force increases to 93.27% for part having wall angles of 50 o and 60 o . Furthermore, during forming of asymmetric part, it is observed that the maximum forces go on increasing till the wall angle reaches to 60 o followed by sudden decrease in the forming forces. When compared to forming of symmetric part under similar conditions, it is observed that the symmetric part reaches to its fracture limit earlier as compared to that of asymmetric part. The numerical simulation gives some clear insights in the forming behavior of the asymmetric parts. Furthermore, it is observed that equivalent plastic strain first increases, and then decreases considerably resulting fracture of part of wall angle 65 o .